A pressure contact for connection with at least one other contact has two end parts spaced apart along a longitudinal axis extending from one part to the other part, and a meander spring having spring sections, each of which connects two meander loops. The parts are separated from one another by means of the meander spring which can elastically deform to absorb pressure force exerted by at least one other contact on at least one of the end parts to allow inward movement, yielding to the pressure force, of the one part along the longitudinal axis.
Pressure contacts having meander springs, which are usually a component of a plug-in connector, are known from U.S. Pat. No. 6,783,405 B1 and WO 1996/028865, for example. The contact together with its meander spring is provided either in the plug or in the socket of the plug-in connector, and in conjunction with a suitable other contact forms a pressure-fit electrical connector. The housings of the plug and socket fit complementarily together and can lock to maintain the plug-in connection.
Common application examples of pressure contacts, as disclosed in WO 1996/028865, for example, in particular are interfaces for mobile communication devices such as mobile telephones. By use of the pressure contacts it is possible to transmit various data signals and/or to charge the internal battery of a cell telephone.
The increasing miniaturization of mobile communication devices having an increasingly larger number of functions also requires a reduction in size of the above-described interfaces without impairing the reliability of the interface connections, in particular the electrical connection between the pressure contact and the other contact. The quality of the connection between the pressure contact and other contact is influenced essentially by the elastic tension of the meander spring for the pressure contact and an exact positioning of the engaging parts of the pressure contact and other contact with respect to one another. Besides the selection of suitable material for the meander spring (for example, soft or hard spring steel), for transversely tensioned meander springs known from the prior art the pressure force is specified by the number of meander loops and thus ultimately by the spatial extension of the meandering spring. In the sense of the present patent application, a tensioned meander spring is a spring whose spring section connecting two meander loops is oriented essentially transverse to the pressure force, i.e. transverse to the longitudinal axis.
A pressure contact is known from U.S. Pat. No. 6,200,151 that by means of a specially designed C-spring is intended to compensate for motion of the part outside the motion path lying on the longitudinal axis. However, in this approach as well the C-spring is pretensioned in the region of the part by means of the housing, and the part is also ultimately guided in this manner. Thus there is some lateral shifting and a need to provide a guide for the pressure contact to keep it aligned.
A solid connection of the parts of the pressure contact and other contact requires a certain minimum size of the contact areas of the parts, in particular of the other contact, since the end part for the pressure contact is laterally tilted when a meander spring is used. Although this area may be reduced in size, a guide for the part is then necessary on the sides of the housing for the pressure contact in order to reliably prevent lateral tipping.
It is apparent that the known pressure contacts, due to their space requirement for the meander spring and the mutual contact areas of the pressure contact and other contact, or for a guide usually formed by the housing of the plug-in connector, no longer meet the demands for increasing miniaturization of such modules.